Publications by authors named "Diane Lucente"

34 Publications

Mutations causing Lopes-Maciel-Rodan Syndrome are huntingtin hypomorphs.

Hum Mol Genet 2021 Jan 11. Epub 2021 Jan 11.

Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.

Huntington's disease (HD) pathogenesis involves a genetic gain-of-function toxicity mechanism triggered by the expanded HTT CAG repeat. Current therapeutic efforts aim to suppress expression of total or mutant huntingtin, though the relationship of huntingtin's normal activities to the gain-of-function mechanism and what the effects of huntingtin-lowering might be are unclear. Here, we have re-investigated a rare family segregating two presumed HTT loss-of-function variants associated with the developmental disorder, Lopes-Maciel-Rodan syndrome (LOMARS), using whole genome sequencing of DNA from cell lines, in conjunction with analysis of mRNA and protein expression. Our findings correct the muddled annotation of these HTT variants, reaffirm they are the genetic cause of the LOMARS phenotype and demonstrate that each variant is a huntingtin hypomorphic mutation. The NM_002111.8: c.4469 + 1G > A splice donor variant results in aberrant (exon 34) splicing and severely reduced mRNA, whereas, surprisingly, the NM_002111.8: c.8157 T > A NP_002102.4: Phe2719Leu missense variant results in abnormally rapid turnover of the Leu2719 huntingtin protein. Thus, while rare and subject to an as yet unknown loss-of-function intolerance at the population level, bona fide HTT loss-of-function variants can be transmitted by normal individuals leading to severe consequences in compound heterozygotes due to huntingtin deficiency.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/hmg/ddaa283DOI Listing
January 2021

Patterns of CAG repeat instability in the central nervous system and periphery in Huntington's disease and in spinocerebellar ataxia type 1.

Hum Mol Genet 2020 Aug;29(15):2551-2567

Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.

The expanded HTT CAG repeat causing Huntington's disease (HD) exhibits somatic expansion proposed to drive the rate of disease onset by eliciting a pathological process that ultimately claims vulnerable cells. To gain insight into somatic expansion in humans, we performed comprehensive quantitative analyses of CAG expansion in ~50 central nervous system (CNS) and peripheral postmortem tissues from seven adult-onset and one juvenile-onset HD individual. We also assessed ATXN1 CAG repeat expansion in brain regions of an individual with a neurologically and pathologically distinct repeat expansion disorder, spinocerebellar ataxia type 1 (SCA1). Our findings reveal similar profiles of tissue instability in all HD individuals, which, notably, were also apparent in the SCA1 individual. CAG expansion was observed in all tissues, but to different degrees, with multiple cortical regions and neostriatum tending to have the greatest instability in the CNS, and liver in the periphery. These patterns indicate different propensities for CAG expansion contributed by disease locus-independent trans-factors and demonstrate that expansion per se is not sufficient to cause cell type or disease-specific pathology. Rather, pathology may reflect distinct toxic processes triggered by different repeat lengths across cell types and diseases. We also find that the HTT CAG length-dependent expansion propensity of an individual is reflected in all tissues and in cerebrospinal fluid. Our data indicate that peripheral cells may be a useful source to measure CAG expansion in biomarker assays for therapeutic efforts, prompting efforts to dissect underlying mechanisms of expansion that may differ between the brain and periphery.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/hmg/ddaa139DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7471505PMC
August 2020

Quality of life and caregiver burden in familial frontotemporal lobar degeneration: Analyses of symptomatic and asymptomatic individuals within the LEFFTDS cohort.

Alzheimers Dement 2020 08 13;16(8):1115-1124. Epub 2020 Jul 13.

Mayo Clinic, Rochester, Minnesota, USA.

Objective: The Longitudinal Evaluation of Familial Frontotemporal Dementia Subjects evaluates familial frontotemporal lobar degeneration (FTLD) kindreds with MAPT, GRN, or C9orf72 mutations. Objectives were to examine whether health-related quality of life (HRQoL) correlates with clinical symptoms and caregiver burden, and whether self-rated and informant-rated HRQoL would correlate with each other.

Methods: Individuals were classified using the Clinical Dementia Rating (CDR ) Scale plus National Alzheimer's Coordinating Center (NACC) FTLD. HRQoL was measured with DEMQOL and DEMQOL-proxy; caregiver burden with the Zarit Burden Interview (ZBI). For analysis, Pearson correlations and weighted kappa statistics were calculated.

Results: The cohort of 312 individuals included symptomatic and asymptomatic individuals. CDR plus NACC FTLD was negatively correlated with DEMQOL (r = -0.20, P = .001), as were ZBI and DEMQOL (r = -0.22, P = .0009). There was fair agreement between subject and informant DEMQOL (κ = 0.36, P <.0001).

Conclusion: Lower HRQoL was associated with higher cognitive/behavior impairment and higher caregiver burden. These findings demonstrate the negative impact of FTLD on individuals and caregivers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/alz.12095DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7534513PMC
August 2020

Prolonged tau clearance and stress vulnerability rescue by pharmacological activation of autophagy in tauopathy neurons.

Nat Commun 2020 06 26;11(1):3258. Epub 2020 Jun 26.

Chemical Neurobiology Laboratory, Center for Genomic Medicine, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 185 Cambridge St CPZN 5400, Boston, MA, 02114, USA.

Tauopathies are neurodegenerative diseases associated with accumulation of abnormal tau protein in the brain. Patient iPSC-derived neuronal cell models replicate disease-relevant phenotypes ex vivo that can be pharmacologically targeted for drug discovery. Here, we explored autophagy as a mechanism to reduce tau burden in human neurons and, from a small-molecule screen, identify the mTOR inhibitors OSI-027, AZD2014 and AZD8055. These compounds are more potent than rapamycin, and robustly downregulate phosphorylated and insoluble tau, consequently reducing tau-mediated neuronal stress vulnerability. MTORC1 inhibition and autophagy activity are directly linked to tau clearance. Notably, single-dose treatment followed by washout leads to a prolonged reduction of tau levels and toxicity for 12 days, which is mirrored by a sustained effect on mTORC1 inhibition and autophagy. This new insight into the pharmacodynamics of mTOR inhibitors in regulation of neuronal autophagy may contribute to development of therapies for tauopathies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-020-16984-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7320012PMC
June 2020

Genetic Risk Underlying Psychiatric and Cognitive Symptoms in Huntington's Disease.

Biol Psychiatry 2020 05 17;87(9):857-865. Epub 2019 Dec 17.

Medical Research Council Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurology, School of Medicine, Cardiff University, Cardiff, United Kingdom. Electronic address:

Background: Huntington's disease (HD) is an inherited neurodegenerative disorder caused by an expanded CAG repeat in the HTT gene. It is diagnosed following a standardized examination of motor control and often presents with cognitive decline and psychiatric symptoms. Recent studies have detected genetic loci modifying the age at onset of motor symptoms in HD, but genetic factors influencing cognitive and psychiatric presentations are unknown.

Methods: We tested the hypothesis that psychiatric and cognitive symptoms in HD are influenced by the same common genetic variation as in the general population by 1) constructing polygenic risk scores from large genome-wide association studies of psychiatric and neurodegenerative disorders and of intelligence and 2) testing for correlation with the presence of psychiatric and cognitive symptoms in a large sample (n = 5160) of patients with HD.

Results: Polygenic risk score for major depression was associated specifically with increased risk of depression in HD, as was schizophrenia risk score with psychosis and irritability. Cognitive impairment and apathy were associated with reduced polygenic risk score for intelligence.

Conclusions: Polygenic risk scores for psychiatric disorders, particularly depression and schizophrenia, are associated with increased risk of the corresponding psychiatric symptoms in HD, suggesting a common genetic liability. However, the genetic liability to cognitive impairment and apathy appears to be distinct from other psychiatric symptoms in HD. No associations were observed between HD symptoms and risk scores for other neurodegenerative disorders. These data provide a rationale for treatments effective in depression and schizophrenia to be used to treat depression and psychotic symptoms in HD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.biopsych.2019.12.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7156911PMC
May 2020

Assessment of executive function declines in presymptomatic and mildly symptomatic familial frontotemporal dementia: NIH-EXAMINER as a potential clinical trial endpoint.

Alzheimers Dement 2020 01;16(1):11-21

Department of Neurology, Memory and Aging Center, University of California, San Francisco, San Francisco, CA, USA.

Introduction: Identifying clinical measures that track disease in the earliest stages of frontotemporal lobar degeneration (FTLD) is important for clinical trials. Familial FTLD provides a unique paradigm to study early FTLD. Executive dysfunction is a clinically relevant hallmark of FTLD and may be a marker of disease progression.

Methods: Ninety-three mutation carriers with no symptoms or minimal/questionable symptoms (MAPT, n = 31; GRN, n = 28; C9orf72, n = 34; Clinical Dementia Rating scale plus NACC FTLD Module < 1) and 78 noncarriers enrolled through Advancing Research and Treatment in Frontotemporal Lobar Degeneration/Longitudinal Evaluation of Familial Frontotemporal Dementia Subjects studies completed the Executive Abilities: Measures and Instruments for Neurobehavioral Evaluation and Research (NIH-EXAMINER) and the UDS neuropsychological battery. Linear mixed-effects models were used to identify group differences in cognition at baseline and longitudinally. We examined associations between cognition, clinical functioning, and magnetic resonance imaging volumes.

Results: NIH-EXAMINER scores detected baseline and differences in slopes between carriers and noncarriers, even in carriers with a baseline Clinical Dementia Rating scale plus NACC FTLD Module = 0. NIH-EXAMINER declines were associated with worsening clinical symptoms and brain volume loss.

Discussion: The NIH-EXAMINER is sensitive to cognitive changes in presymptomatic familial FTLD and is a promising surrogate endpoint.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jalz.2019.01.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6842665PMC
January 2020

Utility of the global CDR plus NACC FTLD rating and development of scoring rules: Data from the ARTFL/LEFFTDS Consortium.

Alzheimers Dement 2020 01;16(1):106-117

Mayo Clinic, Jacksonville, Florida, USA.

Introduction: We created global rating scoring rules for the CDR plus NACC FTLD to detect and track early frontotemporal lobar degeneration (FTLD) and to conduct clinical trials in FTLD.

Methods: The CDR plus NACC FTLD rating was applied to 970 sporadic and familial participants from the baseline visit of Advancing Research and Treatment in Frontotemporal Lobar Degeneration (ARTFL)/Longitudinal Evaluation of Familial Frontotemporal Dementia Subjects (LEFFTDS). Each of the eight domains of the CDR plus NACC FTLD was equally weighed in determining the global score. An interrater reliability study was completed for 40 participants.

Results: The CDR plus NACC FTLD showed very good interrater reliability. It was especially useful in detecting clinical features of mild non-fluent/agrammatic variant primary progressive aphasia participants.

Discussion: The global CDR plus NACC FTLD score could be an attractive outcome measure for clinical trials in symptomatic FTLD, and may be useful in natural history studies and clinical trials in FTLD spectrum disorders.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/alz.12033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7202045PMC
January 2020

Nonlinear Z-score modeling for improved detection of cognitive abnormality.

Alzheimers Dement (Amst) 2019 Dec 5;11:797-808. Epub 2019 Dec 5.

UCSF, San Francisco, CA, USA.

Introduction: Conventional Z-scores are generated by subtracting the mean and dividing by the standard deviation. More recent methods linearly correct for age, sex, and education, so that these "adjusted" Z-scores better represent whether an individual's cognitive performance is abnormal. Extreme negative Z-scores for individuals relative to this normative distribution are considered indicative of cognitive deficiency.

Methods: In this article, we consider nonlinear shape constrained additive models accounting for age, sex, and education (correcting for nonlinearity). Additional shape constrained additive models account for varying standard deviation of the cognitive scores with age (correcting for heterogeneity of variance).

Results: Corrected Z-scores based on nonlinear shape constrained additive models provide improved adjustment for age, sex, and education, as indicated by higher adjusted-R.

Discussion: Nonlinearly corrected Z-scores with respect to age, sex, and education with age-varying residual standard deviation allow for improved detection of non-normative extreme cognitive scores.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.dadm.2019.08.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6911910PMC
December 2019

Age at symptom onset and death and disease duration in genetic frontotemporal dementia: an international retrospective cohort study.

Authors:
Katrina M Moore Jennifer Nicholas Murray Grossman Corey T McMillan David J Irwin Lauren Massimo Vivianna M Van Deerlin Jason D Warren Nick C Fox Martin N Rossor Simon Mead Martina Bocchetta Bradley F Boeve David S Knopman Neill R Graff-Radford Leah K Forsberg Rosa Rademakers Zbigniew K Wszolek John C van Swieten Lize C Jiskoot Lieke H Meeter Elise Gp Dopper Janne M Papma Julie S Snowden Jennifer Saxon Matthew Jones Stuart Pickering-Brown Isabelle Le Ber Agnès Camuzat Alexis Brice Paola Caroppo Roberta Ghidoni Michela Pievani Luisa Benussi Giuliano Binetti Bradford C Dickerson Diane Lucente Samantha Krivensky Caroline Graff Linn Öijerstedt Marie Fallström Håkan Thonberg Nupur Ghoshal John C Morris Barbara Borroni Alberto Benussi Alessandro Padovani Daniela Galimberti Elio Scarpini Giorgio G Fumagalli Ian R Mackenzie Ging-Yuek R Hsiung Pheth Sengdy Adam L Boxer Howie Rosen Joanne B Taylor Matthis Synofzik Carlo Wilke Patricia Sulzer John R Hodges Glenda Halliday John Kwok Raquel Sanchez-Valle Albert Lladó Sergi Borrego-Ecija Isabel Santana Maria Rosário Almeida Miguel Tábuas-Pereira Fermin Moreno Myriam Barandiaran Begoña Indakoetxea Johannes Levin Adrian Danek James B Rowe Thomas E Cope Markus Otto Sarah Anderl-Straub Alexandre de Mendonça Carolina Maruta Mario Masellis Sandra E Black Philippe Couratier Geraldine Lautrette Edward D Huey Sandro Sorbi Benedetta Nacmias Robert Laforce Marie-Pier L Tremblay Rik Vandenberghe Philip Van Damme Emily J Rogalski Sandra Weintraub Alexander Gerhard Chiadi U Onyike Simon Ducharme Sokratis G Papageorgiou Adeline Su Lyn Ng Amy Brodtmann Elizabeth Finger Rita Guerreiro Jose Bras Jonathan D Rohrer

Lancet Neurol 2020 02 3;19(2):145-156. Epub 2019 Dec 3.

Dementia Research Centre, Department of Neurodegenerative Disease, Institute of Neurology, University College London, London, UK. Electronic address:

Background: Frontotemporal dementia is a heterogenous neurodegenerative disorder, with about a third of cases being genetic. Most of this genetic component is accounted for by mutations in GRN, MAPT, and C9orf72. In this study, we aimed to complement previous phenotypic studies by doing an international study of age at symptom onset, age at death, and disease duration in individuals with mutations in GRN, MAPT, and C9orf72.

Methods: In this international, retrospective cohort study, we collected data on age at symptom onset, age at death, and disease duration for patients with pathogenic mutations in the GRN and MAPT genes and pathological expansions in the C9orf72 gene through the Frontotemporal Dementia Prevention Initiative and from published papers. We used mixed effects models to explore differences in age at onset, age at death, and disease duration between genetic groups and individual mutations. We also assessed correlations between the age at onset and at death of each individual and the age at onset and at death of their parents and the mean age at onset and at death of their family members. Lastly, we used mixed effects models to investigate the extent to which variability in age at onset and at death could be accounted for by family membership and the specific mutation carried.

Findings: Data were available from 3403 individuals from 1492 families: 1433 with C9orf72 expansions (755 families), 1179 with GRN mutations (483 families, 130 different mutations), and 791 with MAPT mutations (254 families, 67 different mutations). Mean age at symptom onset and at death was 49·5 years (SD 10·0; onset) and 58·5 years (11·3; death) in the MAPT group, 58·2 years (9·8; onset) and 65·3 years (10·9; death) in the C9orf72 group, and 61·3 years (8·8; onset) and 68·8 years (9·7; death) in the GRN group. Mean disease duration was 6·4 years (SD 4·9) in the C9orf72 group, 7·1 years (3·9) in the GRN group, and 9·3 years (6·4) in the MAPT group. Individual age at onset and at death was significantly correlated with both parental age at onset and at death and with mean family age at onset and at death in all three groups, with a stronger correlation observed in the MAPT group (r=0·45 between individual and parental age at onset, r=0·63 between individual and mean family age at onset, r=0·58 between individual and parental age at death, and r=0·69 between individual and mean family age at death) than in either the C9orf72 group (r=0·32 individual and parental age at onset, r=0·36 individual and mean family age at onset, r=0·38 individual and parental age at death, and r=0·40 individual and mean family age at death) or the GRN group (r=0·22 individual and parental age at onset, r=0·18 individual and mean family age at onset, r=0·22 individual and parental age at death, and r=0·32 individual and mean family age at death). Modelling showed that the variability in age at onset and at death in the MAPT group was explained partly by the specific mutation (48%, 95% CI 35-62, for age at onset; 61%, 47-73, for age at death), and even more by family membership (66%, 56-75, for age at onset; 74%, 65-82, for age at death). In the GRN group, only 2% (0-10) of the variability of age at onset and 9% (3-21) of that of age of death was explained by the specific mutation, whereas 14% (9-22) of the variability of age at onset and 20% (12-30) of that of age at death was explained by family membership. In the C9orf72 group, family membership explained 17% (11-26) of the variability of age at onset and 19% (12-29) of that of age at death.

Interpretation: Our study showed that age at symptom onset and at death of people with genetic frontotemporal dementia is influenced by genetic group and, particularly for MAPT mutations, by the specific mutation carried and by family membership. Although estimation of age at onset will be an important factor in future pre-symptomatic therapeutic trials for all three genetic groups, our study suggests that data from other members of the family will be particularly helpful only for individuals with MAPT mutations. Further work in identifying both genetic and environmental factors that modify phenotype in all groups will be important to improve such estimates.

Funding: UK Medical Research Council, National Institute for Health Research, and Alzheimer's Society.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/S1474-4422(19)30394-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7007771PMC
February 2020

The longitudinal evaluation of familial frontotemporal dementia subjects protocol: Framework and methodology.

Alzheimers Dement 2020 01 6;16(1):22-36. Epub 2020 Jan 6.

UCSF, San Francisco, CA, USA.

Introduction: It is important to establish the natural history of familial frontotemporal lobar degeneration (f-FTLD) and provide clinical and biomarker data for planning these studies, particularly in the asymptomatic phase.

Methods: The Longitudinal Evaluation of Familial Frontotemporal Dementia Subjects protocol was designed to enroll and follow at least 300 subjects for more than at least three annual visits who are members of kindreds with a mutation in one of the three most common f-FTLD genes-microtubule-associated protein tau, progranulin, or chromosome 9 open reading frame 72.

Results: We present the theoretical considerations of f-FTLD and the aims/objectives of this protocol. We also describe the design and methodology for evaluating and rating subjects, in which detailed clinical and neuropsychological assessments are performed, biofluid samples are collected, and magnetic resonance imaging scans are performed using a standard protocol.

Discussion: These data and samples, which are available to interested investigators worldwide, will facilitate planning for upcoming disease-modifying therapeutic trials in f-FTLD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jalz.2019.06.4947DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6949411PMC
January 2020

Tracking white matter degeneration in asymptomatic and symptomatic MAPT mutation carriers.

Neurobiol Aging 2019 11 15;83:54-62. Epub 2019 Aug 15.

Department of Radiology, Mayo Clinic, Rochester, MN, USA. Electronic address:

Our aim was to investigate the patterns and trajectories of white matter (WM) diffusion abnormalities in microtubule-associated protein tau (MAPT) mutations carriers. We studied 22 MAPT mutation carriers (12 asymptomatic, 10 symptomatic) and 20 noncarriers from 8 families, who underwent diffusion tensor imaging (DTI) and a subset (10 asymptomatic, 6 symptomatic MAPT mutation carriers, and 10 noncarriers) were followed annually (median = 4 years). Cross-sectional and longitudinal changes in mean diffusivity (MD) and fractional anisotropy were analyzed. Asymptomatic MAPT mutation carriers had higher MD in entorhinal WM, which propagated to the limbic tracts and frontotemporal projections in the symptomatic stage compared with noncarriers. Reduced fractional anisotropy and increased MD in the entorhinal WM were associated with the proximity to estimated and actual age of symptom onset. The annualized change of entorhinal MD on serial DTI was accelerated in MAPT mutation carriers compared with noncarriers. Entorhinal WM diffusion abnormalities precede the symptom onset and track with disease progression in MAPT mutation carriers. Our cross-sectional and longitudinal data showed a potential clinical utility for DTI to track neurodegenerative disease progression for MAPT mutation carriers in clinical trials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.neurobiolaging.2019.08.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6858933PMC
November 2019

Diagnostic evaluation and monitoring of patients with posterior cortical atrophy.

Neurodegener Dis Manag 2019 08 8;9(4):217-239. Epub 2019 Aug 8.

Posterior Cortical Atrophy Program, Frontotemporal Disorders Unit, Massachusetts General Hospital, Boston, MA 02114, USA.

Posterior cortical atrophy (PCA) is a progressive neurocognitive syndrome, most commonly associated with the loss of complex visuospatial functions. Diagnosis is challenging, and international consensus classification and nomenclature for PCA subtypes have only recently been reached. Presently, no established treatments exist. Efforts to develop treatments are hampered by the lack of standardized methods to monitor illness progression. Although measures developed from work with Alzheimer's disease and other dementias provide a foundation for diagnosing and monitoring progression, PCA presents unique challenges for clinicians counseling patients and families on clinical status and prognosis, and experts designing clinical trials of interventions. Here, we review issues facing PCA clinical research and care, summarize our approach to diagnosis and monitoring of disease progression, and outline ideas for developing tools for these purposes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2217/nmt-2018-0052DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6949516PMC
August 2019

Individualized atrophy scores predict dementia onset in familial frontotemporal lobar degeneration.

Alzheimers Dement 2020 01 6;16(1):37-48. Epub 2020 Jan 6.

Department of Neurology, Memory and Aging Center, University of California, San Francisco, San Francisco CA, USA University of California, San Francisco, San Francisco CA, USA.

Introduction: Some models of therapy for neurodegenerative diseases envision starting treatment before symptoms develop. Demonstrating that such treatments are effective requires accurate knowledge of when symptoms would have started without treatment. Familial frontotemporal lobar degeneration offers a unique opportunity to develop predictors of symptom onset.

Methods: We created dementia risk scores in 268 familial frontotemporal lobar degeneration family members by entering covariate-adjusted standardized estimates of brain atrophy into a logistic regression to classify asymptomatic versus demented participants. The score's predictive value was tested in a separate group who were followed up longitudinally (stable vs. converted to dementia) using Cox proportional regressions with dementia risk score as the predictor.

Results: Cross-validated logistic regression achieved good separation of asymptomatic versus demented (accuracy = 90%, SE = 0.06). Atrophy scores predicted conversion from asymptomatic or mildly/questionably symptomatic to dementia (HR = 1.51, 95% CI: [1.16,1.98]).

Discussion: Individualized quantification of baseline brain atrophy is a promising predictor of progression in asymptomatic familial frontotemporal lobar degeneration mutation carriers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jalz.2019.04.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6938544PMC
January 2020

Targeted degradation of aberrant tau in frontotemporal dementia patient-derived neuronal cell models.

Elife 2019 03 25;8. Epub 2019 Mar 25.

Chemical Neurobiology Laboratory, Center for Genomic Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, United States.

Tauopathies are neurodegenerative diseases characterized by aberrant forms of tau protein accumulation leading to neuronal death in focal brain areas. Positron emission tomography (PET) tracers that bind to pathological tau are used in diagnosis, but there are no current therapies to eliminate these tau species. We employed targeted protein degradation technology to convert a tau PET-probe into a functional degrader of pathogenic tau. The hetero-bifunctional molecule QC-01-175 was designed to engage both tau and Cereblon (CRBN), a substrate-receptor for the E3-ubiquitin ligase CRL4, to trigger tau ubiquitination and proteasomal degradation. QC-01-175 effected clearance of tau in frontotemporal dementia (FTD) patient-derived neuronal cell models, with minimal effect on tau from neurons of healthy controls, indicating specificity for disease-relevant forms. QC-01-175 also rescued stress vulnerability in FTD neurons, phenocopying CRISPR-mediated -knockout. This work demonstrates that aberrant tau in FTD patient-derived neurons is amenable to targeted degradation, representing an important advance for therapeutics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7554/eLife.45457DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6450673PMC
March 2019

Population-specific genetic modification of Huntington's disease in Venezuela.

PLoS Genet 2018 05 11;14(5):e1007274. Epub 2018 May 11.

Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States of America.

Modifiers of Mendelian disorders can provide insights into disease mechanisms and guide therapeutic strategies. A recent genome-wide association (GWA) study discovered genetic modifiers of Huntington's disease (HD) onset in Europeans. Here, we performed whole genome sequencing and GWA analysis of a Venezuelan HD cluster whose families were crucial for the original mapping of the HD gene defect. The Venezuelan HD subjects develop motor symptoms earlier than their European counterparts, implying the potential for population-specific modifiers. The main Venezuelan HD family inherits HTT haplotype hap.03, which differs subtly at the sequence level from European HD hap.03, suggesting a different ancestral origin but not explaining the earlier age at onset in these Venezuelans. GWA analysis of the Venezuelan HD cluster suggests both population-specific and population-shared genetic modifiers. Genome-wide significant signals at 7p21.2-21.1 and suggestive association signals at 4p14 and 17q21.2 are evident only in Venezuelan HD, but genome-wide significant association signals at the established European chromosome 15 modifier locus are improved when Venezuelan HD data are included in the meta-analysis. Venezuelan-specific association signals on chromosome 7 center on SOSTDC1, which encodes a bone morphogenetic protein antagonist. The corresponding SNPs are associated with reduced expression of SOSTDC1 in non-Venezuelan tissue samples, suggesting that interaction of reduced SOSTDC1 expression with a population-specific genetic or environmental factor may be responsible for modification of HD onset in Venezuela. Detection of population-specific modification in Venezuelan HD supports the value of distinct disease populations in revealing novel aspects of a disease and population-relevant therapeutic strategies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.pgen.1007274DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5965898PMC
May 2018

Inhibition of p25/Cdk5 Attenuates Tauopathy in Mouse and iPSC Models of Frontotemporal Dementia.

J Neurosci 2017 10 14;37(41):9917-9924. Epub 2017 Sep 14.

Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,

Increased p25, a proteolytic fragment of the regulatory subunit p35, is known to induce aberrant activity of cyclin-dependent kinase 5 (Cdk5), which is associated with neurodegenerative disorders, including Alzheimer's disease. Previously, we showed that replacing endogenous p35 with the noncleavable mutant p35 (Δp35) attenuated amyloidosis and improved cognitive function in a familial Alzheimer's disease mouse model. Here, to address the role of p25/Cdk5 in tauopathy, we generated double-transgenic mice by crossing mice overexpressing mutant human tau (P301S) with Δ mice. We observed significant reduction of phosphorylated tau and its seeding activity in the brain of double transgenic mice compared with the P301S mice. Furthermore, synaptic loss and impaired LTP at hippocampal CA3 region of mice were attenuated by blocking p25 generation. To further validate the role of p25/Cdk5 in tauopathy, we used frontotemporal dementia patient-derived induced pluripotent stem cells (iPSCs) carrying the Tau P301L mutation and generated P301L:Δp35KI isogenic iPSC lines using CRISPR/Cas9 genome editing. We created cerebral organoids from the isogenic iPSCs and found that blockade of p25 generation reduced levels of phosphorylated tau and increased expression of synaptophysin. Together, these data demonstrate a crucial role for p25/Cdk5 in mediating tau-associated pathology and suggest that inhibition of this kinase can remedy neurodegenerative processes in the presence of pathogenic tau mutation. Accumulation of p25 results in aberrant Cdk5 activation and induction of numerous pathological phenotypes, such as neuroinflammation, synaptic loss, Aβ accumulation, and tau hyperphosphorylation. However, it was not clear whether p25/Cdk5 activity is necessary for the progression of these pathological changes. We recently developed the Δ transgenic mouse that is deficient in p25 generation and Cdk5 hyperactivation. In this study, we used this mouse model to elucidate the role of p25/Cdk5 in FTD mutant tau-mediated pathology. We also used a frontotemporal dementia patient-derived induced pluripotent stem cell carrying the Tau P301L mutation and generated isogenic lines in which p35 is replaced with noncleavable mutant Δp35. Our data suggest that p25/Cdk5 plays an important role in tauopathy in both mouse and human model systems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1523/JNEUROSCI.0621-17.2017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5637118PMC
October 2017

WNT/β-Catenin Pathway and Epigenetic Mechanisms Regulate the Pitt-Hopkins Syndrome and Schizophrenia Risk Gene .

Mol Neuropsychiatry 2017 Jul 14;3(1):53-71. Epub 2017 Jul 14.

Chemical Neurobiology Laboratory, Center for Genomic Medicine, Massachusetts General Hospital, Massachusetts, USA.

Genetic variation within the transcription factor locus can cause the intellectual disability and developmental disorder Pitt-Hopkins syndrome (PTHS), whereas single-nucleotide polymorphisms within noncoding regions are associated with schizophrenia. These genetic findings position TCF4 as a link between transcription and cognition; however, the neurobiology of TCF4 remains poorly understood. Here, we quantitated multiple distinct transcript levels in human induced pluripotent stem cell-derived neural progenitors and differentiated neurons, and PTHS patient fibroblasts. We identify two classes of pharmacological treatments that regulate expression: WNT pathway activation and inhibition of class I histone deacetylases. In PTHS fibroblasts, both of these perturbations upregulate a subset of transcripts. Finally, using chromatin immunoprecipitation sequencing in conjunction with genome-wide transcriptome analysis, we identified TCF4 target genes that may mediate the effect of TCF4 loss on neuroplasticity. Our studies identify new pharmacological assays, tools, and targets for the development of therapeutics for cognitive disorders.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1159/000475666DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5582445PMC
July 2017

Corrigendum: SMCHD1 mutations associated with a rare muscular dystrophy can also cause isolated arhinia and Bosma arhinia microphthalmia syndrome.

Nat Genet 2017 05;49(6):969

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ng0617-969cDOI Listing
May 2017

Defining the diverse spectrum of inversions, complex structural variation, and chromothripsis in the morbid human genome.

Genome Biol 2017 03 6;18(1):36. Epub 2017 Mar 6.

Molecular Neurogenetics Unit and Psychiatric and Neurodevelopmental Genetics Unit, Center for Genomic Medicine, and Department of Neurology, Massachusetts General Hospital, Boston, MA, 02114, USA.

Background: Structural variation (SV) influences genome organization and contributes to human disease. However, the complete mutational spectrum of SV has not been routinely captured in disease association studies.

Results: We sequenced 689 participants with autism spectrum disorder (ASD) and other developmental abnormalities to construct a genome-wide map of large SV. Using long-insert jumping libraries at 105X mean physical coverage and linked-read whole-genome sequencing from 10X Genomics, we document seven major SV classes at ~5 kb SV resolution. Our results encompass 11,735 distinct large SV sites, 38.1% of which are novel and 16.8% of which are balanced or complex. We characterize 16 recurrent subclasses of complex SV (cxSV), revealing that: (1) cxSV are larger and rarer than canonical SV; (2) each genome harbors 14 large cxSV on average; (3) 84.4% of large cxSVs involve inversion; and (4) most large cxSV (93.8%) have not been delineated in previous studies. Rare SVs are more likely to disrupt coding and regulatory non-coding loci, particularly when truncating constrained and disease-associated genes. We also identify multiple cases of catastrophic chromosomal rearrangements known as chromoanagenesis, including somatic chromoanasynthesis, and extreme balanced germline chromothripsis events involving up to 65 breakpoints and 60.6 Mb across four chromosomes, further defining rare categories of extreme cxSV.

Conclusions: These data provide a foundational map of large SV in the morbid human genome and demonstrate a previously underappreciated abundance and diversity of cxSV that should be considered in genomic studies of human disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13059-017-1158-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5338099PMC
March 2017

SMCHD1 mutations associated with a rare muscular dystrophy can also cause isolated arhinia and Bosma arhinia microphthalmia syndrome.

Nat Genet 2017 Feb 9;49(2):238-248. Epub 2017 Jan 9.

Molecular Neurogenetics Unit and Psychiatric and Neurodevelopmental Genetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts, USA.

Arhinia, or absence of the nose, is a rare malformation of unknown etiology that is often accompanied by ocular and reproductive defects. Sequencing of 40 people with arhinia revealed that 84% of probands harbor a missense mutation localized to a constrained region of SMCHD1 encompassing the ATPase domain. SMCHD1 mutations cause facioscapulohumeral muscular dystrophy type 2 (FSHD2) via a trans-acting loss-of-function epigenetic mechanism. We discovered shared mutations and comparable DNA hypomethylation patterning between these distinct disorders. CRISPR/Cas9-mediated alteration of smchd1 in zebrafish yielded arhinia-relevant phenotypes. Transcriptome and protein analyses in arhinia probands and controls showed no differences in SMCHD1 mRNA or protein abundance but revealed regulatory changes in genes and pathways associated with craniofacial patterning. Mutations in SMCHD1 thus contribute to distinct phenotypic spectra, from craniofacial malformation and reproductive disorders to muscular dystrophy, which we speculate to be consistent with oligogenic mechanisms resulting in pleiotropic outcomes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ng.3743DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5473428PMC
February 2017

Pathological correlations of [F-18]-AV-1451 imaging in non-alzheimer tauopathies.

Ann Neurol 2017 Jan;81(1):117-128

MassGeneral Institute for NeuroDegenerative Disease, Charlestown, MA.

Objective: Recent studies have shown that positron emission tomography (PET) tracer AV-1451 exhibits high binding affinity for paired helical filament (PHF)-tau pathology in Alzheimer's brains. However, the ability of this ligand to bind to tau lesions in other tauopathies remains controversial. Our goal was to examine the correlation of in vivo and postmortem AV-1451 binding patterns in three autopsy-confirmed non-Alzheimer tauopathy cases.

Methods: We quantified in vivo retention of [F-18]-AV-1451 and performed autoradiography, [H-3]-AV-1451 binding assays, and quantitative tau measurements in postmortem brain samples from two progressive supranuclear palsy (PSP) cases and a MAPT P301L mutation carrier. They all underwent [F-18]-AV-1451 PET imaging before death.

Results: The three subjects exhibited [F-18]-AV-1451 in vivo retention predominantly in basal ganglia and midbrain. Neuropathological examination confirmed the PSP diagnosis in the first two subjects; the MAPT P301L mutation carrier had an atypical tauopathy characterized by grain-like tau-containing neurites in gray and white matter with heaviest burden in basal ganglia. In all three cases, autoradiography failed to show detectable [F-18]-AV-1451 binding in multiple brain regions examined, with the exception of entorhinal cortex (reflecting incidental age-related neurofibrillary tangles) and neuromelanin-containing neurons in the substantia nigra (off-target binding). The lack of a consistent significant correlation between in vivo [F-18]-AV-1541 retention and postmortem in vitro binding and tau measures in these cases suggests that this ligand has low affinity for tau lesions primarily made of straight tau filaments.

Interpretation: AV-1451 may have limited utility for in vivo selective and reliable detection of tau aggregates in these non-Alzheimer tauopathies. ANN NEUROL 2017;81:117-128.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ana.24844DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5319193PMC
January 2017

A 63-Year-Old Man With Progressive Visual Symptoms.

JAMA Neurol 2017 Jan;74(1):114-118

Frontotemporal Disorders Unit, Department of Neurology, Massachusetts General Hospital/Harvard Medical School, Boston.

A 63-year-old man presented with a 4-year history of insidious onset and gradual progression of visual symptoms including right homonymous hemianopsia, alexia, and simultanagnosia with preserved memory. Magnetic resonance imaging, perfusion single-photon emission computed tomography, and fluorodeoxyglucose positron emission tomographic scans revealed strikingly asymmetric left parieto-occipital abnormality. Neuropsychological testing was performed. The differential diagnosis, pathologic findings, genetic testing results, and diagnosis are discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1001/jamaneurol.2016.2210DOI Listing
January 2017

The genomic landscape of balanced cytogenetic abnormalities associated with human congenital anomalies.

Authors:
Claire Redin Harrison Brand Ryan L Collins Tammy Kammin Elyse Mitchell Jennelle C Hodge Carrie Hanscom Vamsee Pillalamarri Catarina M Seabra Mary-Alice Abbott Omar A Abdul-Rahman Erika Aberg Rhett Adley Sofia L Alcaraz-Estrada Fowzan S Alkuraya Yu An Mary-Anne Anderson Caroline Antolik Kwame Anyane-Yeboa Joan F Atkin Tina Bartell Jonathan A Bernstein Elizabeth Beyer Ian Blumenthal Ernie M H F Bongers Eva H Brilstra Chester W Brown Hennie T Brüggenwirth Bert Callewaert Colby Chiang Ken Corning Helen Cox Edwin Cuppen Benjamin B Currall Tom Cushing Dezso David Matthew A Deardorff Annelies Dheedene Marc D'Hooghe Bert B A de Vries Dawn L Earl Heather L Ferguson Heather Fisher David R FitzPatrick Pamela Gerrol Daniela Giachino Joseph T Glessner Troy Gliem Margo Grady Brett H Graham Cristin Griffis Karen W Gripp Andrea L Gropman Andrea Hanson-Kahn David J Harris Mark A Hayden Rosamund Hill Ron Hochstenbach Jodi D Hoffman Robert J Hopkin Monika W Hubshman A Micheil Innes Mira Irons Melita Irving Jessie C Jacobsen Sandra Janssens Tamison Jewett John P Johnson Marjolijn C Jongmans Stephen G Kahler David A Koolen Jerome Korzelius Peter M Kroisel Yves Lacassie William Lawless Emmanuelle Lemyre Kathleen Leppig Alex V Levin Haibo Li Hong Li Eric C Liao Cynthia Lim Edward J Lose Diane Lucente Michael J Macera Poornima Manavalan Giorgia Mandrile Carlo L Marcelis Lauren Margolin Tamara Mason Diane Masser-Frye Michael W McClellan Cinthya J Zepeda Mendoza Björn Menten Sjors Middelkamp Liya R Mikami Emily Moe Shehla Mohammed Tarja Mononen Megan E Mortenson Graciela Moya Aggie W Nieuwint Zehra Ordulu Sandhya Parkash Susan P Pauker Shahrin Pereira Danielle Perrin Katy Phelan Raul E Piña Aguilar Pino J Poddighe Giulia Pregno Salmo Raskin Linda Reis William Rhead Debra Rita Ivo Renkens Filip Roelens Jayla Ruliera Patrick Rump Samantha L P Schilit Ranad Shaheen Rebecca Sparkes Erica Spiegel Blair Stevens Matthew R Stone Julia Tagoe Joseph V Thakuria Bregje W van Bon Jiddeke van de Kamp Ineke van Der Burgt Ton van Essen Conny M van Ravenswaaij-Arts Markus J van Roosmalen Sarah Vergult Catharina M L Volker-Touw Dorothy P Warburton Matthew J Waterman Susan Wiley Anna Wilson Maria de la Concepcion A Yerena-de Vega Roberto T Zori Brynn Levy Han G Brunner Nicole de Leeuw Wigard P Kloosterman Erik C Thorland Cynthia C Morton James F Gusella Michael E Talkowski

Nat Genet 2017 01 14;49(1):36-45. Epub 2016 Nov 14.

Molecular Neurogenetics Unit, Center for Human Genetic Research, Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA.

Despite the clinical significance of balanced chromosomal abnormalities (BCAs), their characterization has largely been restricted to cytogenetic resolution. We explored the landscape of BCAs at nucleotide resolution in 273 subjects with a spectrum of congenital anomalies. Whole-genome sequencing revised 93% of karyotypes and demonstrated complexity that was cryptic to karyotyping in 21% of BCAs, highlighting the limitations of conventional cytogenetic approaches. At least 33.9% of BCAs resulted in gene disruption that likely contributed to the developmental phenotype, 5.2% were associated with pathogenic genomic imbalances, and 7.3% disrupted topologically associated domains (TADs) encompassing known syndromic loci. Remarkably, BCA breakpoints in eight subjects altered a single TAD encompassing MEF2C, a known driver of 5q14.3 microdeletion syndrome, resulting in decreased MEF2C expression. We propose that sequence-level resolution dramatically improves prediction of clinical outcomes for balanced rearrangements and provides insight into new pathogenic mechanisms, such as altered regulation due to changes in chromosome topology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ng.3720DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5307971PMC
January 2017

A novel neurodevelopmental disorder associated with compound heterozygous variants in the huntingtin gene.

Eur J Hum Genet 2016 12 22;24(12):1826-1827. Epub 2016 Jun 22.

Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA.

We report compound heterozygous variants in HTT, the gene encoding huntingtin, in association with an autosomal recessive neurodevelopmental disorder. Three siblings presented with severe global developmental delay since birth, central hypotonia progressing to spastic quadraparesis, feeding difficulties, dystonia (2/3 sibs), prominent midline stereotypies (2/3), bruxism (1/3), high myopia (2/3), and epilepsy (1/3). Whole exome sequencing identified compound heterozygous variants in HTT that co-segregated in the three affected sibs and were absent in an unaffected sib. There were no additional variants in other genes that could account for the reported phenotype. Molecular analysis of HTT should be considered, not just for Huntington's disease, but also in children with a Rett-like syndrome who test negative for known Rett and Rett-like syndrome genes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ejhg.2016.74DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5117927PMC
December 2016

The HTT CAG-Expansion Mutation Determines Age at Death but Not Disease Duration in Huntington Disease.

Am J Hum Genet 2016 Feb;98(2):287-98

Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA; Medical and Population Genetics Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Genetic Modifiers of Huntington's Disease Consortium. Electronic address:

Huntington disease (HD) is caused by an expanded HTT CAG repeat that leads in a length-dependent, completely dominant manner to onset of a characteristic movement disorder. HD also displays early mortality, so we tested whether the expanded CAG repeat exerts a dominant influence on age at death and on the duration of clinical disease. We found that, as with clinical onset, HD age at death is determined by expanded CAG-repeat length and has no contribution from the normal CAG allele. Surprisingly, disease duration is independent of the mutation's length. It is also unaffected by a strong genetic modifier of HD motor onset. These findings suggest two parsimonious alternatives. (1) HD pathogenesis is driven by mutant huntingtin, but before or near motor onset, sufficient CAG-driven damage occurs to permit CAG-independent processes and then lead to eventual death. In this scenario, some pathological changes and their clinical correlates could still worsen in a CAG-driven manner after disease onset, but these CAG-related progressive changes do not themselves determine duration. Alternatively, (2) HD pathogenesis is driven by mutant huntingtin acting in a CAG-dependent manner with different time courses in multiple cell types, and the cellular targets that lead to motor onset and death are different and independent. In this scenario, processes driven by HTT CAG length lead directly to death but not via the striatal pathology associated with motor manifestations. Each scenario has important ramifications for the design and testing of potential therapeutics, especially those aimed at preventing or delaying characteristic motor manifestations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajhg.2015.12.018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4746370PMC
February 2016

CHD8 regulates neurodevelopmental pathways associated with autism spectrum disorder in neural progenitors.

Proc Natl Acad Sci U S A 2014 Oct 7;111(42):E4468-77. Epub 2014 Oct 7.

Molecular Neurogenetics Unit and Psychiatric and Neurodevelopmental Genetics Unit, Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114; Departments of Neurology and Broad Institute of M.I.T. and Harvard, Cambridge, MA 02142

Truncating mutations of chromodomain helicase DNA-binding protein 8 (CHD8), and of many other genes with diverse functions, are strong-effect risk factors for autism spectrum disorder (ASD), suggesting multiple mechanisms of pathogenesis. We explored the transcriptional networks that CHD8 regulates in neural progenitor cells (NPCs) by reducing its expression and then integrating transcriptome sequencing (RNA sequencing) with genome-wide CHD8 binding (ChIP sequencing). Suppressing CHD8 to levels comparable with the loss of a single allele caused altered expression of 1,756 genes, 64.9% of which were up-regulated. CHD8 showed widespread binding to chromatin, with 7,324 replicated sites that marked 5,658 genes. Integration of these data suggests that a limited array of direct regulatory effects of CHD8 produced a much larger network of secondary expression changes. Genes indirectly down-regulated (i.e., without CHD8-binding sites) reflect pathways involved in brain development, including synapse formation, neuron differentiation, cell adhesion, and axon guidance, whereas CHD8-bound genes are strongly associated with chromatin modification and transcriptional regulation. Genes associated with ASD were strongly enriched among indirectly down-regulated loci (P < 10(-8)) and CHD8-bound genes (P = 0.0043), which align with previously identified coexpression modules during fetal development. We also find an intriguing enrichment of cancer-related gene sets among CHD8-bound genes (P < 10(-10)). In vivo suppression of chd8 in zebrafish produced macrocephaly comparable to that of humans with inactivating mutations. These data indicate that heterozygous disruption of CHD8 precipitates a network of gene-expression changes involved in neurodevelopmental pathways in which many ASD-associated genes may converge on shared mechanisms of pathogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.1405266111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4210312PMC
October 2014

Human iPSC models of neuronal ceroid lipofuscinosis capture distinct effects of TPP1 and CLN3 mutations on the endocytic pathway.

Hum Mol Genet 2014 Apr 23;23(8):2005-22. Epub 2013 Nov 23.

Center for Human Genetic Research, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA.

Neuronal ceroid lipofuscinosis (NCL) comprises ∼13 genetically distinct lysosomal disorders primarily affecting the central nervous system. Here we report successful reprograming of patient fibroblasts into induced pluripotent stem cells (iPSCs) for the two most common NCL subtypes: classic late-infantile NCL, caused by TPP1(CLN2) mutation, and juvenile NCL, caused by CLN3 mutation. CLN2/TPP1- and CLN3-iPSCs displayed overlapping but distinct biochemical and morphological abnormalities within the endosomal-lysosomal system. In neuronal derivatives, further abnormalities were observed in mitochondria, Golgi and endoplasmic reticulum. While lysosomal storage was undetectable in iPSCs, progressive disease subtype-specific storage material was evident upon neural differentiation and was rescued by reintroducing the non-mutated NCL proteins. In proof-of-concept studies, we further documented differential effects of potential small molecule TPP1 activity inducers. Fenofibrate and gemfibrozil, previously reported to induce TPP1 activity in control cells, failed to increase TPP1 activity in patient iPSC-derived neural progenitor cells. Conversely, nonsense suppression by PTC124 resulted in both an increase of TPP1 activity and attenuation of neuropathology in patient iPSC-derived neural progenitor cells. This study therefore documents the high value of this powerful new set of tools for improved drug screening and for investigating early mechanisms driving NCL pathogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/hmg/ddt596DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3959814PMC
April 2014

Candidate glutamatergic and dopaminergic pathway gene variants do not influence Huntington's disease motor onset.

Neurogenetics 2013 Nov 4;14(3-4):173-9. Epub 2013 May 4.

Center for Human Genetic Research, Massachusetts General Hospital, Simches Research Building, Room 5414, 185 Cambridge Street, Boston, MA, 02114, USA.

Huntington's disease (HD) is a neurodegenerative disorder characterized by motor, cognitive, and behavioral disturbances. It is caused by the expansion of the HTT CAG repeat, which is the major determinant of age at onset (AO) of motor symptoms. Aberrant function of N-methyl-D-aspartate receptors and/or overexposure to dopamine has been suggested to cause significant neurotoxicity, contributing to HD pathogenesis. We used genetic association analysis in 1,628 HD patients to evaluate candidate polymorphisms in N-methyl-D-aspartate receptor subtype genes (GRIN2A rs4998386 and rs2650427, and GRIN2B rs1806201) and functional polymorphisms in genes in the dopamine pathway (DAT1 3' UTR 40-bp variable number tandem repeat (VNTR), DRD4 exon 3 48-bp VNTR, DRD2 rs1800497, and COMT rs4608) as potential modifiers of the disease process. None of the seven polymorphisms tested was found to be associated with significant modification of motor AO, either in a dominant or additive model, after adjusting for ancestry. The results of this candidate-genetic study therefore do not provide strong evidence to support a modulatory role for these variations within glutamatergic and dopaminergic genes in the AO of HD motor manifestations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10048-013-0364-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3825533PMC
November 2013